Relationships between insect pests and weeds: an evolutionary perspective

Abstract

Weeds are an important plant resource for insects, although feeding by insects on weeds can have both positive and negative effects on crop productivity. Weeds also indirectly affect crops via their influence on beneficial insects, and by harboring plant and insect diseases. Weeds may affect the ability of dispersing insects to locate crop plants. The host relationship between insects and plants is highly variable, ranging from very specialized to generalized feeding behaviors. Despite the myriad interactions of weeds and insects, many aspects of the relationship are predictable. Most insects, including crop pests, are specialists, and preadapted to feed only on some plants, often within a single plant family. Even polyphagous insects often have a distinct preference hierarchy, feeding more widely only when preferred hosts are unavailable. Use of plants by insects is a dynamic interaction, with characteristics of the insect (e.g., mandible structure) and the plant (e.g., allelochemicals) affecting feeding behavior. Thus, weeds that are closely related to crops are particularly important in harboring insects that attack those crops. Crop production practices should seek to sever the taxonomic association between the crop and the weeds found within the crop, and nearby, by eliminating weeds related to the crop. This will make it less likely that insects will move easily from weed to crop plants, that damaging population densities of insects will develop in the field, and that insect vectors that harbor plant diseases will be harbored in the field. Particularly important integrated pest management practices include crop rotation, reduced use of chemical herbicides, and management of weeds in noncultivated areas.

The multifunctional roles of vegetated strips around and within agricultural fields

“…Field margins can support beneficial invertebrates such as natural enemies of pest invertebrates, but also may harbour weeds, pests and diseases (e.g. viruses), which could potentially create a conflict between crop production and biodiversity conservation [9,49,50]. Increased habitat heterogeneity may also have negative impacts on some migratory (grass-eating) species (e.g.…”

Efeito de herbicidas sobre a comunidade de artrópodes do solo do feijoeiro cultivado em sistema de plantio direto e convencional

“…Segundo Strong et al (1984), 45% das espécies de artrópodes utili zam as plantas como fonte de alimentação, seja pela sucção direta da seiva no caso dos insetos fitófagos ou pela dec omposição de re st os ve getais realizada pelos artrópodes detritívoros. Muitos desses ar tr ópodes se alimenta m exclusivamente de plantas daninhas, podendo ter sua sobrevivência comprometida pelo controle dessas plantas invasoras através da aplicação de herbicidas, contribuindo assim para o desequilíbrio da entomofauna, ocasionando po ss ív ei s pr ob le ma s co m in se to s-pr ag a (Capinera, 2005).…”

Arabidopsis thaliana growth more than defense affects Myzus persicae populations

“…M. persicae are found in all parts of the world, including North America, and show a preference for cold and wet environments (Capinera, 2005). Like other aphids, M. persicae possess specialized stylet mouth parts that pierce plant tissue to access phloem (Kettles et al, 2013).…”

“…These feeding characters coupled with the near completion of its genome sequence, small body size, its ability to thrive in a diverse set of environments, and its short generation time make M. persicae well-suited to many experimental designs (Capinera, 2005;Louis & Shah, 2013).…”